What is string tension and why is it important?

Modern music has become so sub-divided and fragmented that there is no longer one turn-key string solution for every playing style or desired sound. At one point in time, there were no standardized string gauges, but John D'Addario Sr. changed all that in 1939 with the introduction of light, medium and heavy gauges for acoustic instruments. Throughout most of the 20th century, standardized electric and acoustic guitar gauges were sufficient for needs. Occasionally, new string gauge combinations were created for specific purposes and string offerings from manufacturers became immense. However, today there are so many popular styles and trends that it is often necessary for players to go outside of standard gauge sets to get the effect they desire. Whether it's open tunings, drop tunings, baritone guitars, 5-string guitars, 7-string guitars or a variety of other reasons, many players are opting to go their own way and customize their string selection and sound.

What determines string tension?

D'Addario uses three pieces of information in order to determine the tension for strings: the Unit Weight of the string, the Scale Length of an instrument and the Frequency of the string when tuned. We then use a formula to calculate the estimated tension for any string on your particular instrument. However, there are other factors which may affect your perception of string tension which must be taken into account. These factors include the flexibility of the instrument top and neck, the string break-angle at the nut and saddle/bridge, the string height or "action" as adjusted at the saddle and truss rod adjustment.

The string diameter alone does not determine a string's tension. By using different wrap wire materials (nickelplated steel, stainless steel, phosphor bronze, etc.) or by varying the ratio between the core and the wrap wire, two strings with the same diameter, tuned to the same pitch, could have two different tensions.

What information should I prepare before I begin to use the String Tension Pro?

While using the String Tension Pro, you will need to know a few details about your instrument and tuning in order to accurately calculate the tension results. We recommend that you determine the scale length of your instrument and confirm the tuning you shall use with that instrument.

Note: Before deciding on a string gauge, always be sure that your instrument is properly "set up." Unusually high action can change the way the string tension feels and can also result in poor intonation.

What determines the scale length of an instrument?

Scale length is the distance between the nut and the saddle which is also considered the vibrating length on your instrument. You can measure the scale length of your instrument by using a tape measure and measuring the distance from the bridge / saddle to the nut.

Why do strings vary in tension with different scale lengths?

The longer the scale length, the higher the tension is for the same string tuned to the same pitch as a shorter scale — for example, a standard Fender™ guitar at 25½" scale has more string tension and will feel stiffer than a standard Gibson™ 24¾" scale guitar, even if both are tuned to the same standard pitch and using the same string set. As a general rule, the shorter scale length instruments require larger gauge strings to offset the loss of tension at pitch and conversely, the longer the scale length of the instrument is, the smaller the gauge.

What is the string scale length and how does it vary from scale length of the instrument?

String scale length is the distance necessary for the string to sit correctly in your instrument. This means that distance from where the ball end sits in the bridge or string through body of your instrument to the nut. This differs from the scale length of the instrument as this is beyond the vibration points and may determine which total length of string you need on your instrument.

Why do I not see the string I would like in the gauge I prefer?

The String Tension Pro is providing gauge choices in a drop down based off of the string properties you have chosen. We shall always provide for all of the string sizes that we currently offer for purchase. If you find that there are instances where the gauge you would like to use is not available in the drop down, this would mean that D'Addario does not have a string currently available in the size or configuration that you are looking for.

Why do I not see a result at the exact tension I have provided?

The String Tension Pro calculates results according to the way D'Addario manufactures our strings for all of the strings that we currently offer. Because our application is calculating results to the exact standards and specifications that D'Addario manufactures our strings to, the result you receive will be with the closest string that we have to match your preferred tension that is available for purchase. In most cases, we will suggest a string set closest to the parameters that you provide comprised of string tensions we currently offer.

Why are the calculated tensions different now than if I calculate the values myself using the old PDF or check the old packaging?

With the recent D'Addario packaging updates you may have begun to see update the tensions published on all of our sets. The changes in the resulting numbers are derived from two points: Tension Calculation and Unit Weight Calculation. We made a change in the Tension calculation by using more decimal precision in our numbers. We eliminated any rounding of decimals that throughout the totality of the calculation could ultimately lead to a greater tension than the actual. We also remodeled the string Unit Weight calculation itself to allow for a more geometrically accurate number. While some tensions may seem to have changed, (+/- lbs. in some cases) these changes have yielded a much more precise representation of our strings and the tension they yield when tuned to pitch, as well as a much more precise representation than the previous published tensions. It is important to note that the tension calculation we provided is only a small part of the much larger calculation that we use to derive our unit weights. We worked hard to ensure that we could get this calculation as close to the actual usage numbers as possible and now believe that we will have the most accurate information that we can possibly provide.

Are the changes in calculated tension from the old to the new model due to changes in how you are manufacturing the strings?

The numbers that we have published on our sets are still ultimately calculations, and geometric modeling of any physical object is never 100% accurate. While the calculated tension numbers may have changed, the tensions have not changed due to any modifications or changes to how we manufacture our strings, nor have these calculations caused us to make any changes in our string design or manufacturing processes.

NEED HELP?

How do I determine my scale length?

For this step you will need either a tape measure or a ruler that can be used over a long distance. The scale length of your instrument can be determined by measuring the distance from the bridge saddle to the nut. Please place the end of your ruler or tape measure at the saddle and measure the distance to the inside of the nut. Please mark this value down.

Please note that most instruments will have a scale length that is the same from string to string. There are exceptions such as the Banjo, which will have a 5th string that varies from the rest of the strings in the set. Please make sure that all of your strings are the same distance so that we can calculate the most accurate tension information for your strings.

To assist you, we have provided a known standard for the instrument you selected the scale length text boxes if that information is available. If there is no information available for that instrument or you do not want to use our suggested standard, please change the numerical values in the text box provided. Here are some examples of standards that scale length standards for use as a reference:

Please use the following numerical formats for entering data into
the Scale length fields including the decimal points:

Inches — 25.50
Millimeters — 647.7

Note — You may switch between the units of measure that you are comfortable with by using the radial buttons marked in (inches) and mm (millimeters). You may also use as many numbers after the decimal points as you are comfortable providing.

Apply to all Button

The APPLY TO ALL box will apply the numerical value you provide in the text box to all of the strings in the set you are creating.

Continue

Please push the CONTINUE button when you are finished entering all of your information. This action will submit the information and will move you onto the next stage of our set builder. If you would like to change any information after hitting CONTINUE, you may return to change this information by using the EDIT button (Show) next to the title SCALE LENGTH. You also have the ability to change all of this information on the results screen.

NEED HELP?

On this page you have the options to change the tuning of your instrument. To assist you, we have we have provided known standards for the instrument you've selected in a drop down box, if we had information available. If there is no information available, you have the ability to change the note and octaves represented per string as described in the Notes and Octaves section below.

Notes and Octaves

The tuning notation of your set will be represented by two sets of values — a letter representing the pitch (A-G) and a number representing the octave (0-9). You may use the drop down boxes to move quickly between each of the values. Please use the plus and minus buttons if you would like to move incrementally through the choices.

Here are examples of standard tunings for popular instruments and their corresponding note / octave combinations to use as a reference:

Note — You may switch between sharps and flats in a tuning by using the radial buttons marked # (Sharps) and b (Flats).

Continue Button

Please push the CONTINUE button when you are finished entering all of your information. This action will submit the information and will move you onto the next stage in our set builder. If you would like to change any information after hitting CONTINUE, you may return to change this information by using the EDIT button (Show) next to the title TUNING. You also have the ability to change all of this information on the results screen.

NEED HELP?

On this page you have the ability to change the end type, construction and material for each string on your instrument. If you have chosen a D'Addario set as a starting point for your custom set, we have provided the correct information for each string in that set for you already. You may change this information if you choose.

Hex Core Wire - A high carbon steel alloythat is six sided in cross section. When usedas the core or "center" of a musical string,the 6 edge points firmly grip every turn of thewrap wire, ensuring a tight wrap and longer-lasting string. Used exclusively on allD'Addario steel core strings.

Please note that the type of construction or material choices available for you to use in your string set are dependent on the end type you have chosen.

End Type

You may choose the drop down marked end type for each string in your set. The end type refers the manner in which you can attach the strings to your instrument. Here are the end types that we have available for usage:

Guitar Ball End — Used with standard acoustic or electric guitar bridges.

Bass Ball End — Used with standard bass guitar bridges

No End — Used for instrument where you tie the end onto the instrument. Used on classical guitars and some world instruments that use nylon based strings.

Nylon Ball End — Also known as a swedge, this special brass ball end is applied to some nylon strings for use on Classical guitars.

Loop End — Used for instruments that have slot or peg that the loop can be placed over such as banjos and mandolins.

Double Ball End — Used on Steinberger TransTrem instruments that require strings with a predetermined length calibrated to work with that instruments tuning system.

Construction

Construction refers to the manufacturing techniques used to produce each type of string. Please note that the construction type available for you to use in your string set is dependent on the end type that you have chosen. Here is a description of the construction types that we have available for usage based on all end types available:

Round Wound — Refers to a string wound with round wrap wire around the core. This is the most common and popular form of string construction and the most familiar feel to most players.

Half Rounds — Refers to strings that first starts out as traditional round wound construction and then is precision ground, carefully removing the tops of the windings through our unique centerless grinding technique for feel similar to flat wounds but with the flexibility and tension of a round wound string.

Semi-Polished — Refers to winding a flattened silver plated copper wire wound onto a multifilament core of a classical string which is then polished to a smooth surface that resembles a flat wound guitar or bass string.

Flat Wound — Refers to winding a flattened stainless steel ribbon wire onto the core of a string which is then polished to a smooth surface.

Homogenous — Singular material type that are also considered unwound strings. This type of string includes monofilament nylon and plain steel loop end and ball end strings.

Material

Material refers to the specific alloy or homogenous materials used in the design of the string you have chosen. Please note that the type of material that is available for you to use in your string set is dependent on the end type and construction that you have chosen. Here is a description of the material types that we have available for usage based for all end types and construction choices:

Wound String Materials
80/20 Bronze — Composed of 80% copper and 20% zinc, commonly referred to as brass. This is the original acoustic string alloy selected by John D'Addario Sr. and John D'Angelico in the 1930's and is a popular choice for recording due to its crisp, deep and projecting tone.

Phosphor Bronze — 92% copper and 8% tin with phosphorous, introduced to string making by D'Addario in 1974. This alloy is synonymous with warm, bright, and well balanced acoustic tone.

ProSteel — D'Addario's unique ProSteels alloy is our brightest and most corrosion resistant wire. ProSteels are preferred by many rock/metal, country and jazz players for their super-bright, crunchy tone and highly textured feel.

Nickel-plated Steel — The industry standard for electric guitar and D'Addario's most popular electric strings. Nickel-plated steel offers perfect balance of dynamic magnetism and smooth, comfortable feel. Their distinctive bright tone is extremely versatile for all styles of music.

Clear Nylon — The traditional standard for classical strings, this material has a balance of warmth, brightness and projection with an ultra-smooth surface preferred by many professionals for its comfortable nail contact.

Black Nylon — A monofilament nylon material considered to have a warmer, mellower tone than clear nylon.

Composite — A monofilament composite material which delivers increased brightness and projection for 3rd/G strings on classical guitars. This material provides a more balanced volume transition between basses and trebles on classical instruments.

Titanium — a dense monofilament material that has a translucent purple hue and a polished, smooth feel. This unique material has a bright tone and increased projection, resulting in more volume, clarity and dynamics

Carbon — Also referred to as Fluorocarbon, these high projecting tone and responsive polymer based strings are exclusively designed with precise diameter specifications for superior intonation.

APPLY PROPERTIES TO CHECKED button

The APPLY PROPERTIES TO CHECKED button will apply the values you have selected in the drops down to each string position you have checked. Simply click on the boxes on the left of each string to check or uncheck the string. Please note that all drop down values above this apply button must be filled in order to apply to the checked strings.

Get Results Button

Please push the GET RESULTS button when you are finished entering all of your information. This action will submit the information and will move you onto the final stage of the set builder. If you would like to change any information after hitting GET RESULTS, you may return to change this information by using the EDIT button (Show) next to the title STRING PROPERTIES. You also have the ability to change all of this information on the results screen.

NEED HELP?

On this page you have the ability to choose the string gauges you would like to use in your set or provide a tension you would like the string to achieve and we shall suggest string gauges for you. Select either GAUGE or TENSION to proceed by using the radial buttons provided for each string. Please note that the Gauge radial button is the default option selected when you arrive at this screen.

Gauge — The finished diameter of a string.
Tension — The amount of pressure a string is under when tuned to pitch. This is also dependent upon your scale length measurement.

Gauge — If you select the GAUGE radial button, a drop down will appear with all currently available string sizes available based off of the string properties you have chosen. Please choose a gauge size for each string that you have selected GAUGE for.

Tension — If you select the TENSION radial button, a text box will appear for you to provide a target tension that you prefer. Based on the string properties you have chosen, we will suggest a string gauge for you closest to the tension you have provided. Please provide a tension for each string that you have selected GAUGE for.

Please use the following numerical formats for entering data into the tension fields including decimal points:

Pounds (lbs.) — 42.55
Kilograms (kg.) — 19.29

Note — You may switch between the units of measure that you are comfortable with by using the radial buttons marked in (inches) and mm (millimeters) for gauge, and lbs. (pounds) and kg (kilograms) for tension. For the tension value, you may also use as many numbers after the decimal points as you are comfortable providing.

Continue Button

Please push the CONTINUE button when you are finished entering all of your information. This action will submit the information and will move you onto the next stage of our set builder. You also have the ability to change all of this information on the results screen.

ABOUT

A Timeline of String Tension

Nearly three decades ago, D'Addario pioneered the practice of publishing string tensions on our product packaging. Based on standard tuning and scale length, these calculations helped give players a greater understanding of what was behind their sound and feel.

Eleven years later, we published the first ever string tension guide, containing unit weights and tensions at various pitches for each string. The guide immediately became an invaluable resource for players looking for more control in their performance.

In 2012, we refined our calculation models to be more accurate than ever. This comprehensive process yielded a more precise representation of our string tensions at pitch, leading directly to our next development: String Tension Pro.

This application's ultimate intent is to educate players about string tension, but also features a number of elements to help musicians achieve a sound and feel perfect for their own unique playing, including the following:

Create custom sets based upon an existing D'Addario set.

Perform tension calculations in real-time so you no longer need to do the math.